"""Logically, this request object should be placed in main.py, however, for
the other modules could access ``request.dataframe`` easily, seperate it
into a single file."""
class request:
    def __init__(self):
        self.name = 'request_name'  # for control_proxy.register_params
        self._dataframe = None
    
    @property
    def dataframe(self):
        """App程序利用该property获取dataframe"""
        tmp = self._dataframe
        self._dataframe = None  # 用过即丢
        
        return tmp
    
    def set_dataframe(self, new_dataframe):
        """dataframe是在main.py中读取串口并更新的"""
        self._dataframe = new_dataframe

request = request()

